Two-cycle gasoline engine



Aug. 18, 1959 G. E. LYVERS TWO-CYCLE GASOLINE ENGINE Filed Jan. 22, 1957 2 Sheets-Sheet 1 //\/VE/VTOR 1 GARLAND E. LYVERS 54%;QMW

ATTORNEY Aug. 18, 1959 G. E. LYVERS 2,399,946

TWO-CYCLE GASOLINE ENGINE Filed Jan. 22, 1957 2 Sheets-Sheet 2 Pig 6 /NVEN7' OR: GARLAND E. LYVERS BK WW ATTORNEY Patented Aug. 18, 1959 ice.

TWO-CYCLE GASOLINE ENGINE Garland E. Lyvers', Racine, Wis.

Application January 22, 1957, Serial No. 635,439 Claims. (Cl. 123-65) This invention relates to a two-cycle gasoline engine, and, more particularly, it relates to a two-cycle gasoline engine wherein the gasoline and oil are not mixed, and the engine has means for improving the charging thereof.

In the modern-day two-cycle gasoline engine, it is common practice to mix lubricating oil with the gasoline in order that the moving parts of the engine be properly lubricated. Of course, this results in a relatively inefiicient engine, since the oil enters the combustion chamber, and the spark plugs eventually become fouled. It is, therefore, a primary object of this invention to provide a two-cycle gasoline engine wherein the oil need not be mixed with the gasoline. In accomplishing this object, the engine operates at a high efficiency, and the spark plug is less likely to become fouled. Nevertheless, the engine is properly lubricated in the usual manner of lubricating a four-cycle engine.

It is another object of this invention to provide a twocycle gasoline engine wherein the air charging and exhaust steps are performed in an improved manner.

Still another object of this invention is to provide a two-cycle engine which does not get too hot, particularly in the wrist pin and piston parts.

Other objects and advantages will become apparent upon reading the following description in conjunction with the accompanying drawings, wherein:

Fig. 1 is a sectional view of a fragment of a preferred embodiment of this invention.

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is an end view of a fragment of Fig. 1.

Fig. 4 is a fragment of Fig. 1, but showing a variation of parts.

Fig. 5 is a fragment of Fig. 1, but showing a variation of parts.

Fig. 6 is a sectional view taken on the line 6-6 of Fig. 5.

Similar reference numerals refer to similar parts among the several views.

The drawings show a fragment of a two-cycle single cylinder gasoline engine including a conventional crank case 10 onto which is suitably bolted a cylinder 11. A crank shaft 12 is rotatably mounted within the crank case 10, and the crank shaft includes the usual eccentric portion 13. The connecting rod 14 is suitably attached to the crank case portion 13 to rotate on the latter, and the connecting rod 14 extends from the crank shaft to the wrist pin 16 which is shown to include an insert 17, and, of course, the end of the connecting rod 14 encircles the wrist pin 16 while a suitable bushing is disposed between the connecting rod and the pin 16. The wrist pin 16 passes through a main piston 18 which is disposed within the cylinder 11 in the usual manner. Thus, upon recip rocation of the piston 18 within the cylinder 11, the crank shaft 12 will be rotated, all in the well-known manner of operation of a gasoline engine.

The important feature of this invention resides in the rod 23 attached thereto with the two rods being mounted on an eccentric 25 integral with the crank shaft 12, as shown, for rotation with the crank shaft. Thus, the two rods 23 and the pistons 22 are shown in Fig. l to be recip- ,rocable in directions opposite to the movement of the piston 18 for a reason which will be apparent later. It is preferred that the stroke of the pistons 22 be at least one half of the length of stroke of the piston 18. The usual wrist pins 24 are provided at the upper ends of the rods 23 to attach the rods to the pistons 22, and also it is preferred that suitable bushings be provided between the rods 23 and the eccentrics 25 on the crank shaft 12. It will be seen that the bores or cylinders 21 extend from the bottom edge of the piston skirt 19 to the openings 26 and 27 in the piston 18 immediately below the main piston wrist pin 16. Also, the wrist pin 16 is provided with openings 28 and 29 which respectively align with the openings 26 and 27, and also the wrist pin core 17 is pro vided with a passageway 31 in direct communication with the openings just mentioned. At-this time it should be mentioned that the engine is in the bottom center position, and also the openings just described are always in the aligned position as shown and are always in com-.

munication with the passageway 31 in the wrist pin.

With the foregoing described arrangement, when the piston 18 is reciprocated, the pistons 22 reciprocate tov 22 become the working chambers for the purpose ofcharging the cylinder 11.with the necessary air and gas for operation of the engine.

as in the customary arrangement of a two-cycle gasoline engine. I I

When the piston 18 is moved position shown towardthe top center position, the pistons 22 move downwardly, and air or air and gasoline mixture is thus drawn into the passageways and openings above the top edges of the pistons 22 to fill the space then vacated by the piston 18. Conversely, when the spark plug fires, and the piston 18 is forced downwardly from the top center position mentioned, back to the bottom center position shown, air in the opening and passageways is forced therefrom andthrough the side port and into the cylinder 11 above the piston 18. Of course, along with this charge of air introduced into the passageways and openings, the necessary charge of gasoline will enter the cylinder through the carburetor shown.

The important advantage of this arrangement is that the oil which would be in the crank case 10 is not mixed with the air entering the cylinder 11 since the air is not taken from the crank case, as in the popular manner of operating a two-cycle engine. Instead, the oil in the crank case 10 is sealed from entering the cylinder 11,

The cylinder 11 is provided with an inlet port 37 and an exhaust port 38 with the two ports in offset position across the cylinder as shown. Thus, in the usual; ar-

rangement, as the piston moves downwardly from top; center to bottom center, the exhaust ,port ,38 is fiIStllIb,

covered by the piston, and then the inlet port .37 is uncovered, and, of course, this permits the expended gases to escape through the exhaust slightly before the inlet; port is uncovered by the downwardly moving piston 18.'

It should thus be lll1d61'-, stood that the air is not drawn from the crank case 10,v

from the bottom center- 3 Of course, the inlet port 37is in communication with the passageway 31 in the wrist pin 16, and thus the air which is compressed below the top of the piston 18 upon downward movement of the latter will move from the passageway 31 and through the-port 37and into the cylinder ll'above the top of 'the piston 18. 1 v

A'conven'tional carburetor 39 is'attached to,the.side of the cylinder on a plate 41 which is suitably. attached to the cylinder to enclose the'inlet port 37.,. Of course, the gasoline moves through. the carburetor 39 when. the air is entering the cylinder 11, and a check valve 42 is shown disposedover the. opening leading from the carburetor to the port 37, and thus the valve 42' prevents the air and gasoline mixture from going back into the carburetor. Of course, after the air and'gasoline mixture have been injectedinto the cylinder'll, the piston 18 moves upwardly to close the port 37 and finally close the port 38, and continuous upward movement of the piston 18 causes the gas and air mixture to be compressed in the cylinder 11 and, therefore, prepared for firing.

An advantage of vthearrangement described with respect to the piston 18 and the ports in the cylinder 11 is that the charging .airpassing into the cylinder through theport37 .comes from a point which is immediately adjacent the inlet port 37. In other words, the charge. of air is not drawn or forced in from the crank case 10 which is generally disposed a greater distance from the inlet port on the cylinder. Thus, the inlet air is better compressed, and released into the cylinder at the most advantageous time. Also, air drawn into the passageway 31 keeps the wrist pin, cylinder, piston, and all other adjacent parts cool to avoid overheating of the engine and simplify cooling the engine. At the same time, the mixture entering the cylinder will be pre-heated, as desired.

Fig. 4 shows an alternative arrangement of mounting the connecting rods 23 for the small. pistons 22. In this arrangement, the rods 23 are modified in form ,to the shown rod 45 and are stationarily mounted by means of a stud'or support 43 which is anchoredin the crank case 10 and connectedto the rod 45 to maintain the latter in a fixedposition. With this arrangement, of course, there would be two connecting rods '45 which are stationary, and then also the pistons 22 are stationary, and the main piston 18 reciprocates up and down over the pistons .22. Air and gasoline would then be drawn into the cylinder 11 above the top of the pistons 22, and the air and the gasoline are also charged into the cylinder when the main piston 18 moves to the bottom center position. Since therods 45 are'thus maintained in afixedposition, the rods have no throw and, therefore, the attending problems with regard to connecting rod throw'do'not arise.

Figs. and 6 show another arrangement of mounting and maneuvering the'connecting rod 23. In this instance, Figs. Sand 6 show the pistons'22 to be provided with two pins 44 and 46, which pass through the pistons 22 and through the connecting rods 47 which are comparable to the rods 23. With the rods 47 attached to the pistons 22'in'the manner shown, therods 47 remain on a line along the axes of the rods. Thus, the rods have no throw. The lower end of each of the rods attaches to a stud 48 which is shown provided with ball bearings 49, and the stud 48 projects between an inner race 51'and an outer'race J52. Theracc's and'projecting end of the stud are disposed within the counter-weight 53 which is formed on the crank shaft to rotate therewith. It will also be noted that the bearing has a ring 54 integral therewith, and the ring encircles the ball bearing races, as best shown in Fig. 5. With'the arrangement shown in'Figs. 5 and 6, rotation'of the crank shaft causes the counter-weight to rotate therewith, but since the ring 54 and stud 48 are related to the counter-Weight'53 through the'ball bearings 49,'thejstud 48 and'th'e ring 54 do not rotate with the couht'er weight 53. Of course, it will further be noted that the ball bearings and 'ther a'cesSZand- 51 are eccentric with respect to the'crank'sha'ft, and, therefore, rotarim of the latter causes the races to move in an eccentric path. The eccentric .movement in turn causeseach of the connecting rods 47 to move in a purely axial direction; that is, in this instance, up and down with the rods having no throw. Here also, it will be noted that the eccentricity of the ball bearing is opposite to that of the crank shaft and, therefore, as the crank shaft goes down, the ball bearings go up, and a lso the reverse action occurs.

While a specific embodiment of this invention has been shown and described, it shou ld be understood that certain changes could be made in the embodiment and, therefore, the invention should be limited only by the scope of the appended claims.

1. In a two-cyclegasoline'engine,the combination comprising an engine cylinder, a first piston reciprocably disposed Within said cylinder and including a skirt portion, a crank case attached to said cylinder, a crank shaft rotatablyrrnounted within said crank case, a wrist pin'attach'ed to said firstpistonat the top of'the' latter 'and extending diametrically thereacross, a connecting rod attached between said crank-shaft and saidwrist pin of said first' piston for rotation of said crank shaft upon reciprocation. of said fifst piston, said first piston" having a bore .in' said skirt portion thereof, a-se'cond piston disposed within said bore reciprocable thc'rewithin, said wrist pin'havi'ng' an air passageway in communication with and above said bore and opening to the side of said'cylinder, 'said cylinder having a portin' communication with'saidpassageway .at the bottom center position of said first pistonand extending tosaid cylinder at a location above said top of said first piston when the latter is jin said bottom .cent'erpositiojn, ,anda rod attached to saidsecond piston for causingsaid pistons to be relatively movable. p

2. A two-cycle gasoline enginecomprising in combination a cylinder having an air intake port in one side thereof, a-crank case attached to said cylinder, a crank shaft rotatably mounted insaid crank case, a main piston reciprocably disposed in said cylinder for movementover said intake porttoabottom position where the top of said piston is below the top bfsaidintakeport and said piston ncl d ng swri tp av ganair p ag way n co wli ation wit said po d g t b ttom P io of the stroke of said main piston and includinga skirt rw cn wit two. es th rein in commu a o .y i

said passageway and disposed' below the'latten a con bores there in disposed parallel to said cylinder, a

case, a crank shaft rotatably mounted within said crank case, a con ecti ng rod attached between said crank shaft and said main piston for rotation of said crank: shaft upon reciprocation grand main pistonga secondary pist on disposed within each of said boresand relatively inevable therewithin, said rnain piston having an air assageway in communicationwith andabove said bores and in communication with said inlet port of said cylinder when said piston is in a bottom position.

4. In a two-cycle gasoline engine, the combination comprising an engine cylinder having an inlet portin the side thereof, a' first piston reciprocably disposed within said cylinder and including a skirt portion with a' bore therein, a crankcase attached'fto s aid cylinder, a crank shaft rotatably mounted within said, crank case and" including two oppositely: disposed eccentrics rotatable Withsaid crank shaft, a connecting rod attached between one of said eccentrics on said'crank shaft and said first-piston for rotation of said crank shaft upon reciprocation of said first piston, a second piston disposed within said bore and reciprocable therewithin, a second connecting rod attached between the other of said eccentrics and said second piston for reciprocation of said second piston in the direction opposite to that of said first piston when the latter is adjacent the bottom of its stroke, a wrist pin connected to said first piston and having an air passageway in communication with and above said bore and opening to the side of said cylinder for communication with said inlet port at said bottom of the stroke of said first piston.

5. In a two-cycle gasoline engine, the combination comprising an engine cylinder, a piston reciprocably disposed in said cylinder and including a skirt portion, a crank case attached to said cylinder, a crank shaft rotatably mounted within said crank case, a wrist pin attached to said piston at the top thereof above said skirt portion and extending diametrically thereacross, a connecting rod attached between said crank shaft and said wrist pin for rotation of said crank shaft upon reciprocation of said piston, said piston having a bore in the skirt portion thereof and said bore being open to said crank case, said wrist pin having an opening through the side thereof toward the piston bottom position, said wrist pin having an air passageway in communication with said opening and extending to one side of said cylinder, said cylinder having a port in full flow communication with said passageway at the bottom position of said piston during a length of the stroke, and said port being in direct flow communication with said cylinder above the top of said piston when the latter is in said bottom center position.

References Cited in the file of this patent UNITED STATES PATENTS 990,082 Traub Apr. 18, 1911 1,058,026 Anderson Apr. 8, 1913 1,070,719 Norris Aug. 19, 1913 1,174,765 Roessle et al Mar. 7, 1916 1,186,350 Wagner June 6, 1916 1,212,310 Avilla Jan. 16, 1917 1,326,733 Hulse Dec. 30, 1919 1,337,077 Kershaw Apr. 13, 1920 1,542,463 Lyreman et a1 June 16, 1925 2,270,597 Merrell J an. 20, 1942 FOREIGN PATENTS 470,397 France June 15, 1914 

